1. Field of the Present Invention
The present invention generally relates to the field of electronic signal cables and more particularly to cables used to connect one or more data processing systems in a data processing network.
2. History of Related Art
Wired computer networks typically include one or more data processing systems that are connected by some form of cabling. Among the most pervasive types of cable are the various types of Ethernet cables. Ethernet refers to network hardware and protocols that comply with IEEE 802.3. Ethernet cables provide the physical medium that connects systems in an Ethernet network. The most common Ethernet networks today are 10 Megabit/second and 100 Megabit/second networks. Many of these networks employ twisted pair wire cabling as the most cost effective means of connecting systems in high data-rate networks.
Referring to FIG. 1A and FIG. 1B, two of the most commonly encountered methods of connecting multiple systems in a LAN are depicted. In FIG. 1A, a xe2x80x9cdirect connectxe2x80x9d network 100 includes a first data processing system 102, a second data processing system 104, and a cable 106 connected between them. Data processing systems 102 and 104 may be implemented with any of a variety of microprocessor based computing systems including laptop and desktop personal computers, server systems, and so forth.
Cable 106 is typically a CAT 5 twisted pair cable that includes 8 wires (4 pairs). In an Ethernet embodiment, these 8 wires include plus and minus transmit wires (T+, Txe2x88x92), plus and minus receive wires (R+, Rxe2x88x92), and four power signals (GND, VDD, etc.). In a direct connect network 100, it is necessary to connect the receive wires of one device to the transmit wires of the other device and vice versa Thus, in FIG. 1A, the R+ connection of system 102 is connected to the T+ connection of system 104, the Rxe2x88x92 connection of system 102 is connected to the Txe2x88x92 connection of system 104 and so forth. This connection configuration is commonly referred to as a xe2x80x9ccrossoverxe2x80x9d connection and the cable 106 that implements the crossover connection is referred to as a crossover cable.
In the network 110 as depicted in FIG. 1B, multiple data processing systems, two of which are represented by systems 112 and 114, are connected to ports 122 and 124 of a hub 120 via cables 16 and 118 respectively. The hub configuration of network 110 beneficially enables multiple systems to connect to a common hardware device to create a LAN that includes several systems. In an Ethernet implementation of network 110, hub 120 is typically configured to connect to systems 112 and 114 using a xe2x80x9cpass throughxe2x80x9d configuration in which the T+/xe2x88x92 and R+/xe2x88x92 signals of the individual systems connect to the corresponding signal in the connection ports 122 and 124. Thus, for example, the T+ signal of system 112 is connected to the T+ signal of port 122 on hub 120.
It will be appreciated that it may be desirable to alter network configurations from time to time for any of a variety of reasons. Thus, for example, a particular system or pair of systems may at one time be part of a direct connect network such as network 100 while, at other times, they may comprise a portion of a hub configuration 110. It would be desirable to implement a cable that could accommodate either configuration without significantly increasing the cost or complexity of the cable and without an appreciable loss of reliability.
The problems identified above are in large part addressed by a network cable according to the present invention. The cable includes a set of signal wires connected between a pair of connectors and has at least two configuration settings. In a first configuration setting, the pass-through configuration setting, the cable""s signal wires are connected between like connector pins such that, for example, pin 1 of a first connector is connected to pin 1 of a second connector, pin 2 of the first connector is connected to pin 2 of the second connector and so forth. In a second configuration, the crossover configuration, at least a subset of the signal wires connect unlike connector pins such that for example, pin 1 of the first connector may be connected to pin 3 of the second connector.
The cable is preferably transitionable from the first cable setting to the second cable setting by hand. In one embodiment, the cable includes a substantially cylindrical coupling piece intermediate between the two connectors. The coupling piece receives signal wires from the two connectors and provides a mechanism for coupling the signal wires from the first connector to the signal wires from the second connector. In one embodiment, the cylindrical coupling piece includes an annular outer shell that encloses an inner cylindrical piece. The outer shell may be rotated around the inner piece from a first position to a second position. When in the first position, the cylindrical coupling piece connects the signal wires of the two connectors in a first configuration while, in the second configuration, the coupling piece connects the signal wires in a second configuration.
In other embodiments, the cable may include alternative forms of coupling pieces. In one embodiment, the coupling piece includes a hand settable switch. The position of the switch dictates the coupling configuration such that a first position of the switch enables a first coupling configuration, a second position of the switch enables a second coupling configuration, and so forth. Another embodiment of the coupling piece includes a mechanism that is configured to retract the cable ends when not in use.